There are conventional inkjet recording apparatus known in the art that can record an image on a recording medium by ejecting ink stored in an ink container through nozzles. One such inkjet recording apparatus is configured such that a new ink cartridge can be attached every time ink in an ink cartridge that has been attached is consumed.
Japanese Utility Model Registration Publication No. 3156861 discloses an ink cartridge that can be attached to and detached from a cartridge attachment section of an inkjet recording apparatus. The ink cartridge has a detection mechanism that is used for optical detection of a remaining amount of ink. The detection mechanism includes a movable bar that can pivotally move about a fixed shaft, and a soft support cap. When ink stored in an ink bag is consumed, the ink bag deflates. As the ink bag deflates, the soft support cap also deflates. This causes the movable bar to change its pivoting posture. By optically detecting the change in the pivoting posture of the movable bar, consumption of ink in the ink cartridge can be detected.